US PATENT CLASS 75
Class Notes


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75 /   HD   SPECIALIZED METALLURGICAL PROCESSES, COMPOSITIONS FOR USE THEREIN, CONSOLIDATED METAL POWDER COMPOSITIONS, AND LOOSE METAL PARTICULATE MIXTURES



DEFINITION

Classification: 75/

This is the generic class for specialized metallurgical processes for producing or recovering metals from metal compounds, ores, or scrap metal and for refining liquid metal and for compositions used in these specialized metallurgical processes, consolidated metal powder compositions, and loose metal particulate mixtures.

Included in this class are patents drawn to:

(A) Processes for the production of solid, particulate free metal directly from liquid metal.

(B) Processes for the production or purification of free metal powder or the production or purification of alloys in powder form.

(C) Processes for the production or refining of free metal or alloys that use the electrothermal effects of electricity or electromagnetic wave energy or that use magnetism or electrostatics.

(D) Processes for the production of free metal by smelting, roasting, or furnace methods (a.k.a., pyrometallurgy) or by using a nonmetallic material which is liquid under standard conditions (a.k.a., hydrometallurgy).

(E) Processes for the treatment of liquid metal or melting metal.

(F) Processes for consolidating metalliferous charges or treating agents that are used in other processes of this class by agglomerating, compacting, indurating, or sintering.

(G) Compositions, not elsewhere provided for, disclosed as useful in metallurgical processes (e.g., reactive furnace linings, charges or solid treating compositions for producing free metal or alloys from metalliferous materials, gaseous or liquid compositions used in the production of free metal or alloys or used in the treatment of liquid metal) and processes of manufacturing compositions useful in metallurgical processes.

(H) Consolidated metal powder compositions having a continuous free metal phase, such as those produced by a process of the class of Powder Metallurgy Processes. See Lines With Other Classes and Within This Class, 1., below.

(I) Loose metal particulate mixtures.

LINES WITH OTHER CLASSES

A. LIST OF CLASSES OF CHEMICAL COMPOUNDS AND COMPOSITIONS USED IN METALLURGICAL PROCESSES

148, Metal Treatment.

149, Explosive and Thermic Compositions or Charges.

252, Compositions.

423, Chemistry of Inorganic Compounds.

507, Earth Boring, Well Treating, and Oil Field Chemistry.

508, Solid Anti-Friction Devices, Materials Therefor, Lubricant or Separant Compositions for Moving Solid Surfaces.

B. LIST OF CLASSES OF FREE METAL PRODUCTS 148, Metal Treatment.

420, Alloys or Metallic Compositions.

428, Stock Material or Miscellaneous Articles.

502, Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making.

C. LIST OF PROCESS CLASSES

65, Glass Manufacturing.

148, Metal Treatment.

164, Metal Founding.

204, Chemistry: Electrical and Wave Energy.

209, Classifying, Separating, and Assorting Solids.

241, Solid Material Comminution or Disintegration.

264, Plastic and Nonmetallic Article Shaping or Treating: Processes.

266, Metallurgical Apparatus.

419, Powder Metallurgy Processes.

420, Alloys or Metallic Compositions.

423, Chemistry of Inorganic Compounds.

502, Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making.

505, Superconductor Technology: Apparatus, Material, Process.

588, Hazardous or Toxic Waste Destruction or Containment.

D. ORDER OF SUPERIORITY AMONG VARIOUS METAL, ALLOY, AND METAL STOCK AREAS AND METHODS OF MANUFACTURE INVOLVING THEM.

The order of superiority among various metal, alloy, and metal stock areas and methods of manufacture involving them is as follows:

1. Class 419, Powder Metallurgy Processes.

2. Class 148, Metal Treatment, subclasses 22+, compositions for treatment of solid metal. 3. Class 75, Specialized Metallurgical Processes, Compositions for Use therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 300,301, and 303+, gaseous, liquid, or solid treating compositions for liquid metal or charges, and subclass 302, welding rod defined by composition.

4. Class 75, Specialized Metallurgical Processes, Compositions for Use therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 228+, consolidated metal powder compositions and subclasses 255+, loose metal particulate mixtures.

5. Class 420, Alloys or Metallic Compositions, claimed as products.

6. Class 148, Metal Treatment, subclasses 95-122, 194-287, and 500-714, in class schedule order, providing for certain processes of treating solid or semi-solid metal by modifying or maintaining internal physical structure (i.e., microstructure) or chemical properties of metal, processes of reactive coating of metal or processes of chemical-heat removing (e.g., flame-cutting etc.) or burning of metal. However, if metal casting, fusion bonding, machining, or working is involved, there is a requirement of significant heat treatment as described in the Class 148 definition, Lines With Other Classes, "Metal Casting, Metal Fusion

Bonding, Machining, or Working Classes".

7. Class 148, Metal Treatment, subclasses 33+, barrier layer stock material and subclasses 400+, stock.

8. Class 75, Specialized Metallurgical Processes, Compositions for Use therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 331+, processes of making solid particulate alloys directly from liquid metal and subclasses 343+, processes of producing or purifying alloys in powder form.

9. Class 75, Specialized Metallurgical Processes, Compositions for Use therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 10.1+ and 10.67, processes of making alloys by electrothermic, electromagnetic, or electrostatic processes.

10. Class 420, Alloys or Metallic Compositions, processes of manufacture.

11. Class 75, Specialized Metallurgical Processes, Compositions for Use therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 330+, processes of making metal and processes or treating liquid metals and liquid alloys and consolidating metalliferous material.

12. Class 204, Chemistry: Electrical and Wave Energy, processes.

13. Class 164, Metal Founding, subclasses 1+, processes. 14. Class 266, Metallurgical Apparatus, subclasses 44+, processes of operating metallurgical apparatus.

15. Class 216, Etching a Substrate: Processes.

This list is not complete and may be added to as the proper relationship of other areas is determined.

The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, subsection COMPOSITION CLASS SUPERIORITY, which includes a hierarchical ORDER OF SUPERIORITY FOR COMPOSITION CLASSES.

REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS

65, Glass Manufacturing,

19+, for processes of treating (e.g., quenching, etc.),

recovering, or manufacturing products from slag where no making of elemental metal is claimed, and subclass 141 for apparatus for treating slag with a liquid. Class 65 will take processes where the slag is identified as being obtained from a metal manufacturing process (e.g., blast furnace slag, etc.), as long as no positive step of making metal is claimed. (Process class)

148, Metal Treatment, appropriate subclasses for certain processes of treating solid or semi-solid metal by modifying or maintaining the internal physical structure (i.e., microstructure) or chemical properties of metal, processes of reactive coating of metal or processes of chemical-heat removing (e.g., flame-cutting etc.) or burning of metal. (Process class) 164, Metal Founding, appropriate subclasses, particularly

55.1+, for an alloying or refining step when performed during casting which includes treating while teeming or while in the mold. Class 75 provides for a process of refining combined with a Class 164 process (significant or nominal). The refining for Class 75 is done outside of a mold. (Process class)

148, Metal Treatment,

22+, for compositions employed in the treatment of solid metal (e.g., masking compositions, welding compositions, soldering fluxes, compositions for treating heated solid metal, etc.). (Class of chemical compounds and compositions used in metallurgical processes)

148, Metal Treatment, for elemental metal or alloys which (a) are the product of a Class 148 process (e.g., heat treated, age hardened); (b) are claimed in terms of specific magnetic properties or as having particular internal structure which affects the magnetic properties; (c) are amorphous; (d) possess the property of shape memory; (e) are the product of a significant Class 164, Metal Founding, step (e.g., chill cast, directionally solidified), or (f) are the product of the dispersion of particulate matter in molten metal which particulate matter retains its identity in the final product (e.g., dispersion strengthened etc.). (Class of free metal products)

149, Explosive and Thermic Compositions or Charges, for exothermic compositions for treating metalliferous materials. See

5+, 20+, 30+, or 37+ for compositions which (1) contain at least one free metal or metalloid and at least one Oxygen (O) supplying material and (2) are capable of reacting to yield heat and reaction by-products. The line between Class 149 and Class 75 is difficult due to the similarity of ingredients in the compositions. If there is a positive recitation of exothermic utility, the original goes to Class 149 even if

the composition is used in a Class 75 process. If the composition is used in a Class 75 process and there is no positive recitation of exothermic utility, it goes to Class 75 as an original. Patents having claims to both a Class 75 process and a Class 149 composition go to Class 75 as original and are crossed to Class 149. (Class of chemical compounds and compositions used in metallurgical processes)

204, Chemistry: Electrical and Wave Energy, appropriate subclasses for the preparation of metals, alloys, and products of utility only as intermediary products in a metallurgical process by electrical or wave energy methods including chemical reactions which are caused by more than the mere thermal effects of the electrical or wave energy. Lacking positive indication of more than a thermal effect, processes producing metals, treating metals, producing alloys or treating alloys go to Class 75. Branching processes wherein one branch comprises a process falling within the definition of Class 204 and wherein at least one branch comprises a process falling within the definition of Class 75 are classified in Class 75. Combinations of metallurgical process steps falling within the definition of Class 75 and electrical or wave energy process steps falling under the definition of Class 204, are classified in Class 204 when the metallurgical process steps are preparatory to the electrical or wave energy process steps and are classified in Class 75 when the electrical or wave energy process steps are preparatory to the metallurgical process steps. The foregoing applies even though such preparatory steps result in a desired by-product. (Process class)

209, Classifying, Separating, and Assorting Solids, for concentration processes which involve the separation of ore or metalliferous materials by nonchemical means (e.g., flotation, screening, amalgamation, etc.). Preparatory chemical processes for producing an intermediate for amalgamation, preparatory chemical processes followed by amalgamation, and chemical or physiochemical processes of breaking the amalgam to liberate the desired free metal will be found in Class 75,

388+,. A combination of classifying, separating, or assorting metalliferous material that is to be used in a Class 75 process with consolidation will be found in Class 75. (Process class)

241, Solid Material Comminution or Disintegration, appropriate subclasses, for processes of comminuting or disintegrating solid metal, ore, or metalliferous material for the purpose of reducing their particle size and operations perfecting the same which do not involve a chemical treatment. A combination of comminution or disintegration with a step provided for in Class 75 will be found in Class 75. (Process class) 252, Compositions, for physical separation agents, barrier layer device compositions, magnetic compositions having a

nonmetal matrix, etching or brightening compositions, descaling agents, detergents, getters, electrically conductive compositions, having a nonmetal matrix, radioactive compositions, chemical agents, solids with solution or dispersion aids, solvents, gaseous compositions, and preservative agents. Gaseous compositions and liquid compositions used in metallurgical processes will be found in Class 75,

300,. Solid treating compositions for molten metal or charges will be found in Class 75, subclasses 303+. (Class of chemical compounds and compositions used in metallurgical processes)

264, Plastic and Nonmetallic Article Shaping or Treating: Processes,

5+, for processes of forming solid particulate material directly from molten or liquid mass wherein a material other than metal is comminuted (see Class 75, subclass 331 for an amplification of the line), subclass 15 for spheroidizing or rounding of solid, nonmetallic particles (see Class 75 subclass 342 for an amplification of the line), and appropriate subclasses, particularly 109+, for uniting of bulk assembly particulate materials and for methods of compacting and briquetting nonmetallic particles intended for uses other than Class 75 or Class 420 refining or alloying. (Process class)

266, Metallurgical Apparatus,

44+, for processes of operating metallurgical apparatus which are solely directed to those steps of operating such an apparatus which do not effect a chemical or physical change in the work being treated. (Process class)

419, Powder Metallurgy Processes, appropriate subclasses, for processes of producing metals, alloys, or metal containing compositions in a solid or compact state from powdered or particulate material with or without heating. (Process class)

420, Alloys or Metallic Compositions, for processes of making alloys or metallic compositions. However, processes of making solid particulate alloys or metallic compositions directly from liquid metal will be found in Class 75,

331+, and processes of producing alloys or metallic compositions in powder form will be found in Class 75, subclasses 343+. In the instances in which the above mentioned processes are claimed and a process of making an alloy is claimed in generalized terms the patent will go as an original to Class 75 and a cross reference will be placed in Class 420. Processes of making an alloy by electrothermic, electromagnetic, or electrostatic steps will be found in Class 75, subclasses 10.1+ or subclass 10.67. In the instances in which the electrothermic, electromagnetic, or

electrostatic steps are claimed and a process of making an alloy is claimed in generalized terms the patent will go as an original to Class 75 and a cross-reference will be placed in Class 420. In the instances in which the electrothermic, electromagnetic, or electrostatic steps are claimed and an alloy or metallic composition is claimed as a product, the patent will go as an original to Class 420 and a cross reference will be placed in Class 75. The line between Class 75 and Class 420 is necessarily a difficult one since the metals produced by the processes of Class 75 are often impure and the Class 420 alloys are sometimes made from ores. Therefor, the following lines will be observed. A process of making an alloy of desired composition for an end use will be classified in Class 420 even if made by reducing compounds or ore. A method of reduction or smelting to yield metal without intent to obtain a particular alloy or metallic composition will be classified in Class 75 even if it is recognized that the product is impure. Furthermore, methods of melting, refining, or removing a component from an existing alloy (e.g., purifying, etc.) will be found in Class 75. Melting of two or more metals or alloys together to produce an alloy will be found in Class 420. In the production of a ferroalloy, if the percentages of metals are specified the original will go to Class 420. (Process class)

420, Alloys or Metallic Compositions, for alloys or metallic compositions. An alloy or metallic composition made by consolidating base metal particles or a mixture of metal and nonmetal particles is proper for Class 75, 303+, or subclasses 228+ unless (a) all the components are melted or dissolved or (b) a part of the components is melted and the mass is treated as a fluent liquid (e.g., stirring, pouring, etc.) in which instances the product is proper for Class 420. Cases of doubt will be resolved in favor of placement in Class 75, subclasses 303+ or subclasses 228+. Class 75, subclasses 303+ or subclasses 255+ provide for compositions containing loose metal particles not elsewhere provided for. Class 420 provides for a free metal or a single alloy or metallic composition in particulate form. However, a blend of free metal particles or alloy or metallic composition particles with other particles whether another free metal, another alloy or metallic composition, or a nonmetal is proper for Class 75, subclasses 303+ or subclasses 255+. Class 420 also provides for patents claiming an article by name only without any positive structural limitation and reciting the metal or alloy or metallic composition of which the article is made. (Class of free metal products)

423, Chemistry of Inorganic Compounds, for inorganic compounds and nonmetallic elements, including metal compounds useful in metallurgical processes of obtaining free metals. Solid treating compositions for molten metal or charges for producing metal or treating molten metal, including compositions for or from consolidating, will be found in Class 75. (Class of chemical compounds and compositions used

in metallurgical processes)

423, Chemistry of Inorganic Compounds, appropriate subclasses, for processes for chemically modifying metalliferous material (e.g., ore, scrap, etc.) to form products which comprise inorganic compounds even if intended for subsequent reduction to free metals. Processes recovering metal values go to Class 423 unless it can be determined conclusively that free metal (i.e., zero valent) is the metal value obtained, in which case the patent is placed as an original in Class 75. A smelting process is assumed to produce a free metal unless otherwise stated. Class 423,

1+, provide for processes of beneficiating a metalliferous ore where no free metal is obtained and the product is not consolidated. Beneficiation processes are classified in the first subclass under subclass 1 providing for the metal value recovered. Processes which simply remove an impurity from an ore without identifying any specific metal present (e.g., roasting, desulfurizing, dephosphorizing, or dearsenizing ore, etc.) are placed in subclass 1. Class 75, subclasses 746+ provide for consolidating metalliferous material (e.g., ore, tailings, flue dust, fluxes, etc.) by agglomerating, compacting or heat treating; preparatory process therefore; or treating consolidated material therefrom even though the production of a free metal is not claimed. Processes resulting in the production or separation of undesired metal (e.g., impurities, etc.) during the manufacture of Class 423 compounds are classified in Class 423. However, if the metal removed is recovered as a desired product, the patent is classified in Class 75. Recovery of the metal is assumed to be a process to produce a desired product for an end use unless otherwise stated. Patents including claims classifiable in Class 423 and equally comprehensive claims classifiable in Class 75 are classified in Class 75 and cross-referenced to Class 423. (Process class)

428, Stock Material or Miscellaneous Articles, for material or articles having some structure. In general, when claims mention the article by name only and define it in terms of composition, the original goes to the composition class. (Class of free metal products)

502, Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making, for compositions that are used as catalysts, solid sorbents, and their supports even if they are made of metal or metal compounds. (Class of free metal products)

502, Catalyst, Solid Sorbent, or Support Therefor: Product or Process of Making, for processes of producing or rehabilitating metals or metalliferous products intended for use as a catalyst, sorbent, or support therefor. (Process class)

505, Superconductor Technology: Apparatus, Material, Process,

300+, for metallurgical operation similar to Class 75 operations that involve material superconducting above 30 degrees Kelvin. (Process class)

507, Earth Boring, Well Treating, and Oil Field Chemistry, for earth boring and well treating compositions. (Class of chemical compounds and compositions used in metallurgical processes) 508, Solid Anti-Friction Devices, Materials Therefor, Lubricant or Separant Compositions for Moving Solid Surfaces, and Miscellaneous Mineral oil Compositions, for lubricant compositions. (Class of chemical compounds and compositions used in metallurgical processes)

588, Hazardous or Toxic Waste Destruction or Containment, appropriate subclasses for the use of metals (molten or otherwise) in the destruction or containment of hazardous or toxic waste. (Process class)

GLOSSARY:

(Asterisked * terms are employed in section C, Chemistry and Metallurgy of the International Patent Classification (IPC) and have the same meaning herein.)

Synonyms of names of metal elements used in this class (mostly obsolete) are listed below. The names used in this class are in capital letters, the synonyms in lower case.

Aldebaranium = YTTERBIUM (Yb); Argentum = SILVER (Ag); Aurum = GOLD (Au); Ausonium = NEPTUNIUM (Np); Austrium = GALLIUM (Ga)

Cassiopeium = LUTETIUM (Lu); Celtium = LUTETIUM (Lu); Columbium = NIOBIUM (Nb)

Demonium = DYSPROSIUM (Dy); Didymium = NEODYMIUM (Nd) and PRASEODYMIUM (Pr); Dwimanganese = RHENIUM (Re)

Eka - aluminum = GALLIUM (Ga); Ekaboron = SCANDIUM (Sc); Ekacesium = FRANCIUM (Fr); Ekamanganese = TECHNETIUM (Tc); Ekasilicon = GERMANIUM (Ge); Ekatantalum = PROTACTINIUM (Pa); Erythronium = VANADIUM (V)

Ferrum = IRON (Fe); Florentium = PROMETHIUM (Pm)

Glucinum = BERYLLIUM (Be); Hydrargyrum = MERCURY (Hg)

Illinium = PROMETHIUM (Pm); Kalium = POTASSIUM (K) Lutecium = LUTETIUM (Lu); Masurium = TECHNETIUM (Tc)

Natrium = SODIUM (Na); Neoytterbium = YTTERBIUM (Yb)

Plumbum = LEAD (Pb)

Stannum = TIN (Sn); Stibnium = ANTIMONY (Sb)

Virginium = FRANCIUM (Fr); Wolfram = TUNGSTEN (W)

ACTINIDE*

A metal of the group Actinium (Ac), Thorium (Th), Protactinium (Pa), Uranium (U), Neptunium (Np), Plutonium (Pu), Americium (Am), Curium (Cm), Berkelium (Bk), Californium (Cf), Einsteinium (Es), Fermium (Fm), Mendelevium (Md), Nobelium (No), and Lawrencium (Lr).

ALKALI METAL*

A metal of the group Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).

ALKALINE EARTH METAL*

A metal of the group Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). ALLOY

A union, possessing metallic properties of two or more metallic elements or of nonmetallic element (s) and metallic elements(s) which are not pure compounds and which are miscible with each other, which at least to a certain extent when molten forms a more or less homogeneous liquid having a metallic matrix and which does not separate into distinct layers when solid. Such combinations when solidified from a melt may consist of mechanical mixtures, entectics, entectoids, solid solutions, or in part of chemical compounds one or more of which may exist at the same time. Intermetallic compounds are considered alloys for purposes of classification.

(1) Note. The term "alloy" when used in the various definitions of Class 75 is considered to include a "metallic composition" (q.v.) of the type that is found in Class 420.

AMALGAMATION

The use of a liquid metal to collect, to alloy, or to adhere a desired free metal without melting the desired free metal with heat.

BASE

A metal which is present in an amount of over 50% by weight in an alloy.

BESSEMER CONVERTER

A device having passages in its bottom (i.e., tuyeres) through which a gas containing gaseous Oxygen (e.g., air,

etc.) is passed upwardly through molten metal or molten metalliferous material (e.g., matte, etc.) to treat the metal or material.

BLAST FURNACE

A type of shaft furnace specifically designed to reduce metal compounds (e.g., ore, etc.) to elemental metal using a combustible solid reductant (e.g., coke, etc.). The furnace is designed to operate continuously for a long period of time, with solid reductant, metal compound, and any other desired solid additive (e.g., flux, etc.) being continuously or periodically added at the top of the furnace and the resulting molten metal and by-product slag being continuously or periodically tapped from the bottom of the furnace. A gas containing gaseous Oxygen (e.g., air, etc.) is preheated (usually by the exhaust gas) and is injected into the furnace through tuyeres above the molten metal and slag level. CEMENTATION

A process of recovering a free metal from solution wherein a more electropositive free metal displaces a less electropositive metal from solution as a free metal while the more electropositive metal goes into solution in ionic form.

CONSOLIDATE

To form into a compact mass.

CRUCIBLE FURNACE

A furnace in which the material to be heated is placed in a refractory container, the container is covered with a lid, and the covered container is heated in a furnace. The material is heated solely by heat conducted through the walls of the crucible.

CUPOLA

A shaft furnace primarily designed to melt metal by use of a solid fuel charged with the metal. A gas containing gaseous Oxygen (e.g., air) is blown into the bottom of the furnace to burn the fuel and cause the metal to melt from the heat of combustion.

DISPLACEMENT REACTION FOR METALS

In the reaction A + BC = AC + B, the metal A, being more positive than the metal B, is oxidized. The displacement series or electromotive series for metals in decreasing order of their negative potentials is: (negative) Vanadium (V), Tungsten (W), Molybdenum (Mo), Gold (Au), Osmium (Os), Platinum (Pt), Iridium (Ir), Tantalum (Ta), Palladium (Pd), Ruthenium (Ru), Antimony (Sb), Bismuth(Bi), Arsenic (As), Mercury (Hg), Silver (Ag), Copper (Cu), Titanium (Ti), Tin (Sn), Lead (Pb), Germanium (Ge), Zirconium (Zr), Cerium (Ce),

Nickel (Ni), Cobalt (Co), Thallium (Tl), Niobium (Nb), Cadmium (Cd), Iron (Fe), Chromium (Cr), Zinc (Zn), Manganese (Mn), Uranium (U), Gadolinium (Gd), Indium (In), Gallium (Ga), Aluminum (Al), Rare Earth Metals, Beryllium (Be), Scandium (Sc), Yttrium (Y), Magnesium (Mg), Lithium (Li), Calcium (Ca), Strontium (Sr), Barium (Ba), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) (positive).

FLUIDIZED BED A bed of solid particles with gas flowing upward through the particles with sufficient velocity to keep the particles suspended and in motion in the gas without blowing them bodily out of the top of the bed. The suspended particles act much like a fluid.

GASEOUS SUSPENSION

The suspension of solid in gas. This may be in a fluidized bed (q.v.) or in any other system (such as a conduit) where solids are suspended in a gas.

HALOGEN*

An element of the group Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At).

HEAVY METAL*

A metal other than a light metal (q.v.).

HYDROMETALLURGY

A somewhat inexact term for processes involving solution in water or other liquid in which metalliferous material or metal is treated to prepare free metal, to purify, or to refine free metal, or to prepare intermediate materials more suitable for use in preparing free metal (e.g., extracting, leaching, beneficiating, etc.).

IRON GROUP

An element of the group Iron (Fe), Cobalt (Co), and Nickel (Ni).

LANTHANIDE* A metal of the group Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Th), Ytterbium (Yb), and Lutetium (Lu).

LIGHT METAL*

A metal of the group Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr), Calcium (Ca),

Strontium (Sr), Barium (Ba), Radium (Ra), Beryllium (Be), Magnesium (Mg), and Aluminum (Al).

METAL*

Element other than nonmetal (q.v.).

METALLIC COMPOSITION

A composition which contains a continuous phase of metal and no continuous phase of nonmetal.

MUFFLE FURNACE

A furnace in which the material to be heated is placed in an enclosed section (the muffle), which protects the material from the combustion products of the furnace. The material is heated by heat conducted through the walls of the muffle.

NOBLE GAS*

An element of the group Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (X), and Radon (Rn). NOBLE METAL*

A metal of the group Ruthenium (Ru), Rhodium (Rd), Palladium (Pd), Osmium (Os), Iridium (Ir), Platinum (Pt), Silver (Ag), and Gold (Au).

NONMETAL*

An element of the group Hydrogen (H), Boron (B), Carbon (C), Silicon (Si), Nitrogen (N), Phosphorus(P), Oxygen (O), Sulfur (S), Selenium (Se), Tellurium (Te), Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At), Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rd).

(1) Note. For subclasses 228+ Silicon is considered to be a metal.

PLATINUM GROUP*

An element of the group Osmium (Os), Iridium (Ir), Platinum (Pt), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd).

PRECIOUS METAL

Synonym for Noble Metal (q.v.).

PYROMETALLURGY

A somewhat inexact term for processes carried out at relatively high temperatures, usually in furnaces, in which metalliferous material or metal is treated to prepare free metal, to purify or to refine free metal, or to prepare

intermediate materials more suitable for use in preparing free metal (e.g., smelting, bessemerizing, roasting of ores, etc.). RADIOACTIVE ELEMENT

An element of the group Technetium (Tc), Promethium (Pm), Polonium (Po), Astatine (At), Radon (Rn), Francium (Fr), Radium (Ra), Actinium (Ac), Thorium (Th), Protactinium (Pa), Uranium (U), Neptunium (Np), Plutonium (Pu), Americium (Am), Curium (Cm), Berkelium (Bk), Californium (Cf), Einsteinium (Es), Fermium (Fm), Mendelevium (Md), Nobelium (No), Lawrencium (Lr), Unnilquadium (Unq), Unnipentium (Unp), and Unnilhexium (Unh).

RARE EARTH METAL*

An element of the group Scandium (Sc), Yttrium (Y), Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), and Lutetium (Lu).

REFRACTORY METAL*

A metal of the group Titanium (Ti), Zirconium (Zr), Hafnium (Hf), Vanadium (V), Niobium (Nb) or Columbium (Cb), Tantalum (Ta), Chromium (Cr), Molybdenum (Mo), and Tungsten (W).

REVERBERATORY FURNACE

An enclosed furnace in which the material to be heated is placed in the bottom of the furnace and gaseous fuel is burned over the top of the material or the flame or combustion products from burning solid fuel separately from the material to be heated are reflected by the top of the furnace and passed over the material. Types of reverberatory furnace are the Siemen-Martin furnace, the open hearth furnace, and the puddling furnace.

ROTARY KILN

An approximately cylindrical apparatus which rotates on its axis in operation. The axis is horizontal or inclined less than 45 degrees from horizontal. Usually, the axis is slightly inclined from horizontal. In operation the kiln rotates substantially continuously in one direction.

SCRAP

Discarded waste metal suitable for reprocessing. SHAFT FURNACE

A vertical approximately cylindrical apparatus in which material to be treated is passed downwardly through the shaft while it is heated in any manner. In this class the material

treated in the furnace is usually either reduced to free metal or melted or both.

SYNONYMS

See the beginning of the Glossary section for a list of synonyms of names of metal elements used in this class (mostly obsolete).

TRANSITION METAL*

A metal of the group Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Yttrium (Y), Zirconium (Zr), Niobium (Nb) or Columbium (Cb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag), Cadmium (Cd), Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), Mercury (Hg), Actinium (Ac), Thorium (Th), Protactinium (Pd), Uranium (U), Neptunium (Np), Plutonium (Pu), Americium (Am), Curium (Cm), Berkelium (Bk), Californium (Cf), Einesteinium (Es), Fermium (Fm), Mendelevium (Md), Nobelium (No), Lawrencium (Lr), Unnilquadium (Unq), Unnilpentium (Unp), and Unnilhexium (Unh).

VERTICAL RETORT

A vertical, generally cylindrical, vessel closed at the bottom and heated externally so that the contents are heated only by heat conduced through the retort walls. Often a product is volatilized from the retort and collected in another container.